1. Field of the Invention
This invention relates to flare burners and more specifically to apparatus for the combustion of combustible waste gas from refineries and the like.
2. Description of the Prior Art
It is common practice to burn waste gas from refineries and the like. A commonly used structure for this purpose comprised a central gas pipe of a diameter in the range from 24 to 30 inches, surrounded by a large insulated cylinder of the order of 30 feet in diameter and from 15 to 50 feet in height. The major objection to this design is that the gas being burned is concentrated in one central area with inadequate surface area for mixing air for combustion with the gas. The diffusion of the gas and air has a great effect upon the surface area of the flame and this was not taken into account with many of the structures of that type. Diffusion is also dependent upon the Reynolds number, that is whether it is a laminar or turbulent type of mixing.
While the combustion can and has been improved using stacks of that type they are expensive and difficult to erect and may have maintenance problems aggravated by the necessity for repairs at the top of the stack.
It has also been proposed to provide a multi-jet ground flare in which a series of smaller gas delivery pipes, of about 2 inch diameter on 6 inch centers, connected to one or more manifolds and enclosed within an insulated cylindrical enclosure carried on supporting legs, with flame retention rods above the upper end of each of the gas delivery pipes. With this structure, serious mechanical problems arise because of thermal expansion. The stainless steel gas manifold that feeds the smaller gas nozzle is adversely effected by radiation on the top of the manifold which passes through the insulation, and it tends to heat up the top of the pipe. The lower section of the manifold has no thermal radiation from it so that differential expansion occurs and the manifold tends to bow. The use of insulation on the manifold has not proven to be effective.
The flame retention rods referred to above are usually of a length of 30 to 40 feet. These rods have a very short life because of their tendency to burn up and involve difficulties as to their mounting and support and their tendency to bow because of thermal expansion.
Frank, U.S. Pat. No. 1,807,977 and Frost, et al., U.S. Pat. No. 2,971,605 show a plurality of burners.
It is preferred where feasible and is essential under certain conditions to employ a flare in which a plurality of waste gas burners at the same level are employed.
In my prior U.S. Pat. No. 3,703,349, a ground flare is disclosed for incinerating waste combustible gas. The structure there disclosed while satisfactory for some purposes, has shortcomings, including limitations as to location, susceptibility of damage by rain, relatively high weight of the assembled enclosure, and undesirable noise trnsmission to the surrounding area.
In accordance with the present invention a flare burner of the ground flare type is provided which has a plurality of waste gas burners for simultaneous operation, which may be utilized as a ground flare or which may in a modified form be elevated and provided with a heat shield for use on the top of a building or on board a ship, which can optionally be provided with additional combustible liquid waste burners, in one or more of the side walls, of the combustion chamber, which has a combustion chamber with wall panels and which has provisions to reduce the horizontal noise transmission.
It is the principal object of the invention to provide an improved flare burner for waste combustible gas which is of simplified construction, which is light in weight, which operates at a lower outside skin temperature, which is better adapted for operation under rainy conditions, which heats quickly and cools quickly, which has fewer problems of expansion and contraction and which greatly reduces noise transmission.
It is a further object of the invention to provide a flare burner which operates at a low level and does not project flame into the air to great heights as with many of the flare stack burners now in use.
It is a further object of the invention to provide a flare burner which has a wide range of adaptability and usefulness for the incineration of combustible refinery wastes.
Other objects and advantageous features of the invention will be apparent from the description and claims.